KR20220052983A - Heating, ventilation and air conditioning systems based on micro coolers - Google Patents

Abstract

A heating, ventilation, and air conditioning system in which a primary water loop is used as a heat transfer reservoir for heating and cooling. A plurality of micro-coolers are provided, each micro-cooler connected to a primary water loop. Each microcooler contains its own heat engine. Each micro-cooler includes one or more fan control units that exchange heat between the micro-cooler and the air within the building. In a first mode, the microcooler transfers heat from the air in the building to the water circulating in the primary water loop. In a second mode, the microcooler transfers heat from the water circulating in the primary water loop to the air in the building. A primary water loop conditioning system is provided to control the temperature of the water circulating in the primary water loop.

Description

Heating, ventilation and air conditioning systems based on micro coolers

This non-provisional patent application claims priority over the previously filed provisional application. This provisional application lists the same inventor. It was filed on August 26, 2019 and assigned No. 61/891,581.

The present invention relates to the fields of heating, ventilation, and air conditioning. More particularly, the present invention includes a novel system in which local micro-coolers are used instead of a centralized heating and cooling facility.

The present invention can be used in buildings of various sizes and configurations. It will be of general application to commercial structures and a brief description of the existing systems used in these buildings will aid the reader's understanding. The reader should note that various types of systems are currently in use. The description below relates to only one exemplary prior art system. However, it will suitably serve as a basic understanding of the prior art and will also help the reader understand the advantages of the present invention.

1 shows a multi-storey building 10 . Heating, Ventilation, and Air-Conditioning (“HVAC”) are provided by large centralized units. The chiller facility 14 and the hot water facility 16 are located on the roof, or in large facility spaces underground. The chiller facility cools the water and circulates it throughout the building to provide cooling as needed. Heat is discharged from the chiller installation via a cooling tower 24 - located above the roof. The cooled water is circulated through a cold water loop (not shown in FIG. 1 ).

The hot water facility 16 heats the water and circulates it throughout the building in a hot water loop. The hot water loop is separate from the cold water loop. Each layer 12 includes one or more air conditioners 18 . An air duct system 20 extends from each air conditioner 18 . Cold water is provided to each air conditioner 18 through a cold water loop and hot water is provided to each air conditioner through a hot water loop. In some systems, hot and cold water are mixed inside or near an air conditioner. In other systems separate hot and cold water coils are provided inside each air conditioner and the hot and cold water supplies remain separate.

The temperatures required for the hot and cold water loops in the example of FIG. 1 are dictated by the maximum possible cooling and heating loads. As an example, the cold water loop may be sufficiently cold to meet the maximum cooling required of any air conditioner. In large commercial buildings it is common to cool the water in the chilled water loop to approximately 7°C (45°F). This provides adequate cooling performance for the peak demand that may arise from one of the air conditioners in the building. Peak demand occurs very rarely, and maintaining the cold water loop at such a low temperature greatly reduces the overall efficiency of conventional systems.

The water in the hot water loop is typically maintained at approximately 50 to 60 °C (122 to 140 °F). This temperature provides adequate performance for peak heating in either air conditioner. For cold water loops, peak demand is rare and maintaining hot water at such elevated temperatures is inefficient.

2-4 provide additional details related to the prior art system shown in FIG. 1 . 2 shows one exemplary configuration of a chiller facility, a cooling tower, and a chilled water loop. There are various heat engine cycles used in chiller installations. In the example of Figure 2, a compressor-based cycle is used. The cooler facility 14 is typically a vapor-compression cooling system. Input power 34 provides electricity to the compressor and control components. A heat engine inside the chiller facility cools the water circulating in the chilled water loop 28 and also heats the water circulating in the cooling tower circuit 32 .

A circulation pump 26 moves water in the cold water loop 28 through air conditioners 18 . When cooling is required, cold water flow through a specific air conditioner is activated and a fan inside the air conditioner moves the air over a heat exchanger (“coil”) where the cold water is pumped. This interaction cools the air, which is then circulated through the attached air duct system. Flow control valves are used to control the flow of cold water through a specific air regulator. These valves are not shown in FIG. 2 .

A pump 30 delivers the heated water in the cooling tower circuit 32 to the cooling tower 24 , in this example mounted on a roof. The cooling tower may be of an open-loop evaporative or closed-loop type. In either case, the heat transferred by the water in the cooling tower circuit 32 is transferred to the air drawn through the cooling tower. The cooled water then flows back to the cooler facility 14 .

3 shows an example of an exemplary hot water loop 40 . Hot water facility 16 is often referred to as a “boiler” but in this example hot water is circulated as a heat medium (some systems use steam). In the example shown, natural gas is supplied to the facility via a gas inlet 36 and the exhaust gases are carried away by a flue 38 . Natural gas is combusted to heat the water circulating in the hot water loop 40 . The circulation pump 27 circulates the heated water throughout the building.

In this example, each of the air conditioners 18 may receive hot water as needed. Flow control valves are used to control the flow of hot water through a specific air regulator. As this is a cold water example, these valves are not shown in FIG. 3 . Some systems allow the flow of hot and cold water to be regulated separately through each of the air conditioners. Other systems regulate heat transfer by simply turning the flow on or off, and also adjusting the fan speed and/or the “dwell” of the water flow.

4 shows further details of one air conditioner 18 on one floor of a building. A main fan 44 drives air through an air conditioner onto a coil connected to the hot water loop (heat exchanger) and a coil connected to the cold water loop. Air is supplied to the air conditioner from two sources. The first is recirculation air drawn through one or more recirculation resistors 71 . The second source of air is outside air drawn in through the inlet 46 .

The flow rate of the chilled water from the chilled water loop 28 through the air regulator is regulated in this example by a throttling valve 58 . The flow rate of the hot water from the hot water loop 40 is regulated by a throttling valve 56 . Air flow is regulated by air valves 50 , 52 , 54 . The entire control system regulates these components. Operating modes and features include:

1. The throttling valves are limited in their operating range so that the desired temperature can be set in the air regulator by allowing total cold water flow and limited hot water flow.

2. The desired mixing of fresh air may be provided by actuating the interval between air valve 52 fully closed and air valves 50 and 54 open. In this mode the recirculation fan 42 is activated to blow the recirculated air to the outlet 48 . The main fan 44 is operated to draw in outside air through the intake port 46 .

3. A regenerable filter is provided at the inlet (46).

4. A mixture of recirculated air and fresh air may be distributed through distribution duct 74 and delivery resistors 72 by closing air valve 50 and regulating air valves 52 and 54 .

5. The intake 46 may be one or more large trunks, supplying the entire building, rather than one intake for each floor or each air conditioner.

6. Outlet 48 may be one outlet for the entire building with all of the air conditioners feeding to one outlet.

Of course, in most large buildings most floors will have more than one air conditioner. 5 provides a top view of one layer 70 . Solar loads are usually important in commercial buildings. For many days the side of the floor facing the sun may need air conditioning, while the shady side of the same floor may need heating. It is common to divide a floor into five HVAC zones as shown in FIG. 5 . These zones are the central zone 60 , the east zone 62 , the north zone 64 , the west zone 66 , and the south zone 68 . A separate air conditioner is usually provided for each of these zones.

6 shows the same floor plan with the addition of five air conditioners and their associated ductwork. The air conditioners are central zone air conditioner 76 , east zone air conditioner 78 , north zone air conditioner 80 , west zone air conditioner 82 , and south zone air conditioner 84 . A main duct with branches extends from each air conditioner. In this kind of system, each of the air conditioners is connected to a cold water loop and a hot water loop. In the exemplary prior art system, each air conditioner operates independently to provide a desired temperature within an associated zone.

Although these conventional systems provide adequate heating and cooling, they are not very efficient. As previously explained, the cold water loop must be kept low enough to satisfy the maximum cooling demand for one air conditioner. This requires a supply of approximately 7°C (45°F) water. Such cold water will seldom be needed, but must be maintained to meet local peak demand. The same problem exists with the hot water loop, where approximately 60 to 70° C. of water must be provided even though such high temperatures are only needed at one or two points in the entire building.

In a typical commercial building, an HVAC facility uses an average of 235 kW of power per 1,000 kWR of cooling. This gives a coefficient of performance (COP) of 4.25. When the most advanced oil-free compression technology is used, power consumption can be as low as 109 kW per 1,000 kWR (COP of 9.1).

Most commercial HVAC systems are powered by electricity produced from fossil fuels. Carbon dioxide emissions are now a recognized worldwide problem. Power generation is a major contributor to carbon dioxide emissions, with approximately 10,000 tonnes of carbon dioxide being released into the environment for every 1 MWh of electricity produced. Commercial buildings account for a large proportion of electricity demand, and in most commercial buildings, the largest consumer of electricity is air conditioning.

Air conditioning in most existing commercial buildings is provided by chiller facilities. Approximately 80% of all chillers sold today are used to replace and upgrade existing equipment. The remaining 20% is used for new construction. Retrofit capability is therefore an obvious goal of a new kind of HVAC system. In the present invention, there is no need to replace the ductwork and air treatment units as a whole. This can be maintained with all appropriate variants. This advanced system can replace most existing commercial HVAC systems.

Thus, the present invention is applicable to both existing buildings and new constructions. While conventional systems provide a COP of 9.1 to 4.0, the present invention can provide a COP in excess of 14.0. Therefore, the present invention saves a significant amount of electricity while producing the same result.

The present invention includes heating, ventilation, and air conditioning systems in which a primary water loop is used as a heat transfer reservoir for heating and cooling. A plurality of micro-coolers are provided, each of which is connected to a primary water loop. Each microcooler includes its own heat engine. Each micro-cooler includes one or more fan control units that exchange heat between the micro-cooler and the air in the building. In a first mode, the microcooler transfers heat from the air in the building to the water circulating in the primary water loop. In a second mode, the microcooler transfers heat from the water circulating in the primary water loop to the air in the building. A primary water loop conditioning system is provided to control the temperature of water circulating in the primary water loop.

The overall control system preferably controls all components to operate in an efficient manner. In many working examples, the real effect of this progressive system will be in transferring heat from one part of the building to another, rather than using external energy for heating or cooling.

1 is an elevation view showing a conventional HVAC system in a multi-story building;
2 is a schematic diagram, showing the use of a chiller and chilled water circulation loop in a conventional HVAC system;
3 is a schematic diagram, showing the use of a hot water facility and a hot water circulation loop in a conventional HVAC system.
4 is a schematic diagram showing an air conditioner of a conventional HVAC system;
5 is a plan view, showing zones on one floor of a building;
6 is a plan view, showing the use of a plurality of air conditioners and distribution ducts to cover zones on one floor of a building;
7 is an elevation view, showing an HVAC system made in accordance with the present invention;
7B is a plan view, showing an HVAC system made in accordance with the present invention.
8 is a schematic diagram showing the use of a micro cooler to supply a plurality of fan control units;
Fig. 9 is a schematic diagram showing the operation of the device of Fig. 8, in which the fan control units supply heating;
Fig. 10 is a schematic diagram showing the operation of the device of Fig. 8, in which the fan control units supply cooling;
11 is a perspective view showing an exemplary physical embodiment of an inventive micro-cooler.
Fig. 12 is a perspective view showing the embodiment of Fig. 11 from another point of view;
Figure 13 is a perspective view showing the compressor assembly and controller housing for the physical embodiment of Figures 11 and 12;
14 is a schematic diagram, showing the supply of fresh air to the fan control units of one embodiment of the present invention;
15 is a schematic diagram, showing the use of a heat exchanger between the micro-cooler and the primary water loop;
16 is a schematic diagram showing a plurality of micro-coolers connected to a primary water loop through an intermediate water loop.
17 is a schematic diagram, giving the use of an evaporative condenser and boiler to regulate the primary water loop;
18 is a schematic diagram showing the use of a heat pump to regulate a primary water loop.
19 is a schematic diagram, showing a micro-cooler, in which coolant is circulated to the fan control units in a secondary loop;
Fig. 20 is a schematic view, showing the embodiment of Fig. 19, in which the fan control units supply cooling;
FIG. 21 is a schematic view, showing the embodiment of FIG. 19 , in which fan control units supply heating;
22 is a schematic diagram, showing a configuration with a plurality of micro-cooler units, in which coolant is circulated to fan control units in a secondary loop;
23 is a plot of the coefficient of performance of several HVAC systems operating in cooling mode.
24 is a plot of the coefficient of performance of several HVAC systems operating in heating mode.
25 is a plot of pressure ratios as a function of percent load of these advanced and conventional systems.

7 is a schematic diagram, showing how this advanced HVAC system can be installed in a multi-story building 10 . A Primary Water Loop (PWL) 86 flows through the entire building. A circulation pump or pumps (not shown) maintain a constant circulation, although the flow rate can be varied as needed. The PWL regulation system 88 maintains the temperature of the water in the primary water loop at a desired point or within a desired range. Conventional HVAC equipment - such as coolers and boilers - may be used for the PWL control system 88 . Some examples are provided below.

The present invention uses circulating liquids to transfer heat. The circulating liquid is preferably water, and the term “water” includes solutions and mixtures in which corrosion inhibitors and other additives may also be present. The circulating liquids may be other than water, and the present invention is not limited to the use of water. It should be understood that the term water includes any suitable circulating liquid, but for convenience the term water will be used in the descriptions.

The water in the primary water loop is preferably maintained within the range of 16°C to 30°C, more preferably between 18°C and 26°C, and most preferably between 20°C and 24°C (68-76°F). This is a significant difference compared to conventional HVAC systems, where the water in the cold water loop is typically maintained at 7°C or lower (45°F or lower) and the water in the hot water loop is typically maintained at approximately 50°C or higher (approximately 122°F or higher). In the present invention, the water in the PWL is maintained in substantially the same range as the desired air temperature inside the building.

One or more micro-coolers 90 are provided for each floor 12 of the building. Each micro cooler is configured to exchange heat with water circulating in the PWL 86 . Each micro cooler is also configured to exchange heat with one or more associated fan control units 92 (shown in FIG. 7B ). Each fan control unit or units heats or cools the air in the zone it covers.

Referring to FIG. 7 , one of ordinary skill in the art will recognize that primary water loops 86 reaching significant heights can create pressure problems because the pressure near the bottom will be much greater than the pressure near the top. In tall buildings it may often be necessary to separate the PWL into smaller ancillary loops with water-to-water heat exchangers connecting the loops. Other approaches may be used to maintain the water pressure within a desired range. For example, pressure reducing and pressure adding devices may be disposed within the loop. The pressure adding device is usually just a pump. The pressure reducing device may be an intermediate fixed tank on the lowering side of the roof. The intermediate tank receives water from above and discharges the air pressure created in the tank to the atmosphere. Other pressure-regulating devices are known to those skilled in the art. It will be understood that the term “primary water loop” may possibly include such pressure-regulating devices.

8 provides a schematic diagram of one micro cooler 90 and its associated fan control units 92 . The micro cooler 90 is connected to a primary water loop 86 . A tap on the supply line 96 provides circulating water to the micro cooler 90 and a tap on the return line 94 returns water from the micro cooler to the PWL.

The heart of the microcooler in this example is an irreversible heat engine. Compressor 122 compresses the appropriate coolant and sends it to heat exchanger 120 . The heat exchanger 120 operates as a condenser. This cools the circulating coolant and directs it to the expansion valve 124 . The expansion valve expands the liquid coolant and sends it to a heat exchanger 118 , which acts as an evaporator. The evaporator heats the gaseous coolant and directs it back to the suction side of the compressor 122 .

Heat exchanger 118 is cooled by circulating coolant whenever compressor 122 operates. Thus, when the compressor is running, the heat exchanger 120 is heated and the heat exchanger 118 is cooled. Circulation pump 114 pumps water through heat exchanger 118 when activated. Similarly, circulation pump 116 pumps water through heat exchanger 120 when activated. The heat engine in this example is irreversible, meaning that the flow through the coolant loop always travels in the same direction (as opposed to a heat pump which may include a diverter valve to reverse the flow through the evaporator and condenser).

A secondary water loop 126 provides water circulation through one or more fan control units 92 . Each fan control unit includes a coil for water from the secondary water loop and a fan configured to blow air over the coil. If the water circulating through the secondary water loop 126 is hot, the coil of the fan control unit is used to heat the air drawn through the fan control unit. If the water is cold, a fan in the fan control unit is used to cool the air. A distribution duct or ducts are usually connected to each fan control unit. This is not shown in the drawings.

A first set of control valves 98 , 100 , 102 , 104 controls the flow of water through the heat exchanger 118 (evaporator). A second set of control valves 106 , 108 , 110 , 112 controls the flow of water through the heat exchanger 120 (condenser). Additional control valves may be provided in the various branches of the secondary water loop 126 to control flow to each individual fan control unit 92 .

9 and 10 show the micro cooler in two main modes of operation. Figure 9 shows the micro cooler 90 operating in a heating mode in which the fan control units 92 heat the air in their respective zones. Valves 98 and 102 are open. Valves 100 and 104 are closed. Water from the primary water loop enters in supply line 96 and passes through pump 114 . The water then circulates through heat exchanger 118 and exits through valve 102 before reaching return line 94 . Flow paths are shown in bold. The PWL water passing through the heat exchanger 118 cools and returns to the PWL. Stated another way, heat is transferred from the water in the PWL to the microcooler.

Valves 108 and 112 are open. Valves 106 and 110 are closed. Pump 116 pumps water from heat exchanger 120 through valve 108 and directs it to secondary water loop 126 . Water returning from the fan control units of the secondary water loop flows through valve 112 and enters heat exchanger 120 . The water passing through the heat exchanger 120 is heated (recall that the heat exchanger acts as a condenser for the coolant loop) and this heat is transferred to the fan control units. The heated water flowing through the fan control units is used to heat the air. Looking at the overall operation shown in FIG. 9 , heat is drawn from the water circulating in the primary water loop 86 and transferred to the air blown through the fan control units 92 . This is done by connecting PWL 86 to heat exchanger 118 (evaporator) and secondary water loop 126 to heat exchanger 120 (condenser).

Figure 10 shows the same arrangement operating in cooling mode. Valves 106 and 110 are open. Valves 108 and 112 are closed. As in the example above, water from the primary water loop enters supply line 96 . However, unlike the example above, the feed line water is directed to the heat exchanger 120 via a valve 110 . Pump 116 pumps water through heat exchanger 120 and valve 106 . Water from valve 106 is passed back to return line 94 (which re-enters the PWL). Flow paths are shown in bold. The PWL water passing through the heat exchanger 120 is heated and returned to the PWL. Stated another way, heat is transferred from the micro cooler to the water in the PLW.

Valves 98 , 100 , 102 , 104 are set to circulate water from secondary water loop 126 through heat exchanger 118 (evaporator). Valves 100 and 104 are open. Valves 98 and 102 are closed. Pump 114 pumps water through heat exchanger 118 (evaporator) to secondary water loop 126 . Water returning from the fan control units of the secondary water loop is delivered via valve 100 back to pump 114 . The water flowing through the secondary water loop is thereby cooled and the cooled water is used to absorb heat from the building air passing through the fan control units.

Looking at the overall operation shown in FIG. 10 , heat is drawn from the air blown through the fan control units 92 and transferred to the water circulating in the primary water loop 86 . This is done by connecting the PWL 86 to the heat exchanger 120 (condenser) and the secondary water loop 126 to the heat exchanger (evaporator).

The reader should always note that the coolant loops through the heat exchanger 118 and heat exchanger 120 always flow in the same direction (pumped by the compressor). Unlike domestic heat pumps, the coolant loop does not have a diverter valve. Heat exchanger 118 is always an evaporator and heat exchanger 120 is always a condenser.

11-13 show some physical embodiments of this inventive micro-cooler and its components. In this example, the micro cooler 90 is contained within the chassis 128 . Heat exchangers 118 and heat exchanger 120 are mounted near one end of the chassis. Circulation pumps 114 and 116 are mounted near opposite ends. Compressor 122 is contained within the illustrated housing. Interconnecting pipes are provided to create a flow path according to the schematic views of FIGS. 8 and 9 .

12 shows the same micro cooler from a different point of view. From this point of view the reader can observe how the piping ends at the four connection points 132 . Two of these connection points lead to a primary water loop 86 and two of these connection points lead to a secondary water loop 126 . As shown in the schematic diagrams of Figures 8 and 9, the four connection points are all necessary to provide the necessary flow paths.

Turning now to FIG. 11 , the reader should note that all of the flow-control valves for the micro-cooler are provided in one diverter valve assembly 130 in this example. Eight valves can be set to cycle with one movable spool. The switching valves (valves 98, 100, 102, 104, 106, 108, 110, and 112 in FIGS. 9 and 10) are all contained within the switching valve assembly 130 (to avoid confusion, the reader will in this case refer to the term "switching valve assembly ( It should be noted that "reversing valve assembly)" does not refer to a reversing valve inside the coolant circulation loop). The diverter valve assembly 130 may be a spool valve that simultaneously slides a spool through a housing to actuate one or more valves. One of ordinary skill in the art knows that one spool sliding through a suitable housing can include all eight valves 98 , 100 , 102 , 104 , 106 , 108 , 110 , 112 . In this way, one actuator in the valve assembly can provide the necessary switching to operate the microcooler in either heating mode or cooling mode. An additional “idle mode” may also be provided, as will be described below.

Referring to Figure 11, the reader will see that the compressor 122 is quite compact. The compressor is preferably a centrifugal model operating at high speed. The compressor preferably uses ultra-low friction bearing technology. This bearing technology allows the use of an oil-free coolant loop, which greatly increases the efficiency. One approach is to use magnetic bearings that essentially "levitate" the rotating shaft of the compressor. These bearings are very effective, but also very expensive. A cheaper approach is to use foil bearings. Foil bearings have a minimum “liftoff” speed that must be maintained to prevent physical contact in the bearings. This liftoff rate is very low - typically approximately 5% of the rated operating speed of the bearing. The use of these bearings allows very high rotational speeds for the rotating shaft of the compressor. These bearings also allow virtually unlimited "unloading", meaning that the compressor can be operated at a speed much lower than its rated maximum speed without risking contact with the bearings.

As a result of these factors, the compressor 122 is considerably compact and light for its output. 13 shows a physical embodiment of a compressor 122 with an attached controller housing 134 . The controller housing contains start and stop functions, as well as electronics configured to control operation of the compressor throughout its operating range. In preferred embodiments, the compressor will be operated continuously. During periods when heating or cooling is not required, the controlling electronics will minimize rotational speed (down to approximately 10,000 RPM). The controlling electronics will also cycle the microcooler between heating and cooling modes so that the water in the secondary water loop is kept close to the air temperature in the space managed by the microcooler. This idle state consumes more power than just turning off the compressor. However, by continuously operating the compressor above the liftoff speed of the foil bearings, compressor life is extended indefinitely. This operation is referred to as "idle mode". The compressor is "unloaded" - this means that its speed is reduced to a low speed where it is high enough to preserve proper bearing function but the speed of the coolant circulation is greatly reduced. In this idle mode, the eight valves are switched periodically so that the microcooler cycles between heating and cooling modes (eg, once every minute or once every 5 minutes). This allows the compressor to run continuously even when heating or cooling is not required.

Commercial buildings require input of fresh air at specific levels. This is mainly done to minimize the build-up of carbon dioxide. Some conventional systems monitor carbon dioxide levels and introduce fresh air as needed. However, most conventional systems tolerate only a fixed volume of fresh air known experimentally to keep the buildup of carbon dioxide at an acceptable level. 14 shows an embodiment of the present invention that takes a more sophisticated approach.

Fresh air duct 136 carries pressurized fresh air to fan control units 92 . Fresh air admitted to each fan control unit is controlled by an air control valve 138 . Recirculating air is provided to each fan control unit via a recirculating air inlet 140 . The intake of fresh air often places additional loads on the building HVAC system. In hot and humid climates, additional energy is needed to dehumidify and cool the incoming fresh air. Therefore, it may be desirable to tolerate only the required volume of fresh air.

In the illustrated example a carbon dioxide sensor or sensors monitor the carbon dioxide level in each zone and the control system uses this information to adjust the air control valve 138 to introduce as much fresh air as needed - but no more. .

15-18 show further exemplary embodiments. In the example of FIG. 15 , primary water loop 86 is delivered vertically via supply line 96 and return line 94 . A heat exchanger 142 is provided on each floor. The heat exchanger 142 exchanges heat between the primary water loop and the intermediate water loop 144 . The intermediate loop provides circulating water (maintained in the range of 20° C. to 24° C.) to all micro coolers 90 in one bed. Each microcooler then pumps water through its own secondary water loop 126 to the fan control units tied to a particular microcooler.

16 schematically shows an entire floor. The heat exchanger 142 in this example once again exchanges heat between the primary water loop 86 and the intermediate water loop 144 . In this example all micro-coolers in a layer are connected to an intermediate water loop 144 . Three of these micro-coolers are shown (micro-coolers 146, 148, 150). Three secondary water loops 152, 154, 156 are also shown - one for each micro-cooler.

All three micro coolers 146 , 148 , 150 are operating in the same mode - heating mode. However, this need not always be the case. Sometimes micro coolers will operate in different modes. One example is a cool morning with high solar loads in the east zone of the floor. The microcooler operating in the east zone will operate in cooling mode while other microcoolers on the same floor will operate in heating mode. In effect, the east zone micro-cooler will transfer heat from one portion of the bed to another by transferring heat to the intermediate water loop 144 , which heat is again extracted by other micro-coolers on the same floor.

Returning briefly to FIG. 7 , the reader will remember that the temperature of the water circulating within the primary water loop 86 is maintained by the PWL regulation system 88 . Often these systems will have to add heat to the circulating water and also often have to remove heat from the circulating water. A person skilled in the art can use many known devices to regulate the water temperature in the primary water loop.

17 shows an embodiment in which the evaporative condenser 158 and the boiler 160 are used to regulate the water temperature. During times when net cooling is required, an evaporative condenser is operated to transfer heat to the air surrounding the building. Natural gas is burned inside the boiler 160 to raise the water temperature for a period of time when net heating is required. Pump 162 circulates water in primary water loop 86 . The heat exchanger 142 transfers heat between the primary water loop 86 and one intermediate water loop 144 . A plurality of micro-coolers 90 are attached to the intermediate water loop 144 in this example (only one micro-cooler 90 is shown). Additional intermediate water loops (not shown) are also connected to the primary water loop 86 .

18 shows a similar embodiment in which heat pump 168 is replacing the evaporative condenser and boiler of FIG. 17 . Heat pumps are usually used in smaller commercial buildings, but it is also possible to provide service in larger commercial buildings by using multiple heat pumps in parallel.

In the above exemplary embodiments, a secondary water loop was used to transfer heat between a particular micro cooler and its associated fan control units. It is also possible to circulate the coolant directly between the microcooler and its associated fan control units. 19-22 show embodiments using this latter approach. 19 shows the components of another micro cooler 190, while FIGS. 20 and 21 show their operating states. 22 shows a system in which a plurality of micro-coolers are integrated.

In the example of FIG. 19 , compressor 122 pumps coolant to selector valve 170 . The diverter valve directs pressurized (and hot) coolant gas - depending on the mode of operation - to either the heat exchanger 142 or the fan control units 92 . Heat exchanger 142 exchanges heat with primary water loop 86 (intermediate water loops may also be used). As in the previous examples, the heat exchanger 142 transfers heat to the PWL 86 when the fan control units are operating in the cooling mode and receives heat from the PWL when the fan control units are operating in the heating mode. .

Rather than using water circulating a secondary loop to the fan control units, the embodiment of FIG. 19 directs the coolant itself to the fan control units via a coolant circulation loop 188 . The flow of coolant is made reversible through actuation of the diverter valve 170 - as will be explained below. Valves 172 , 174 , 176 , 178 individually control flow to each fan control unit 92 so that the fan control unit can be switched off when heating or cooling is not required in the area it covers. A coil 186 is provided in each fan control unit. This coil operates as either an evaporator or a condenser, depending on the mode of operation.

An expansion valve 180 is provided for each fan control unit 92 . Each expansion valve 180 includes a universal bypass with a check valve 184 . As will be familiar to those skilled in the art, the check valves 184 allow coolant flow to bypass the expansion valves 180 when the fan control units are operated in heating mode. An expansion valve 124 is provided for when the fan control units are operated in the heating mode. A bypass circuit with a check valve 182 allows the expansion valve 124 to be bypassed when the fan control units are operating in the cooling mode.

20 shows the operation of another micro cooler 190 in the cooling mode. The switching valve 170 is set in the cooling position. The compressed coolant gas leaves compressor 122 and is routed through heat exchanger 142 . Heat exchanger 142 acts as a condenser for the cooling circuit. The cooled and condensed liquid coolant leaves heat exchanger 142 and passes around expansion valve 124 by passing through check valve 182 . Liquid coolant then flows to expansion valve 180 in each coil 186 and expanded gas flows through coils 186 (check valve 184 of each bypass circuit is closed by flow in this direction) . Coils 186 are operating as evaporator coils in this mode. A fan in each of the fan control units blows air over the cold coil 186 thereby cooling the air.

Expanded coolant leaving coils 186 is routed back through diverter valve 170 to the suction side of compressor 122 . The reader should note that valves 172,174, 176,178 allow each fan control unit to shut off if cooling is not required in the zone controlled by that particular fan control unit.

21 shows the same embodiment operating in heating mode. The reader will recognize that the selector valve 170 has been changed to its second position. The hot compressed coolant leaves the compressor 122 and is routed through valves 172 - 178 to the coils 186 of the fan control units. In this mode of operation the coils 86 act as condenser coils. A fan in each fan control unit blows air over the heated coils and the air is warmed. The coolant in the coils 186 cools and condenses. The cooled and condensed liquid coolant flows around the expansion valves 180 through the check valves 184 . It is then inflated by the expansion valve 124 (note that the check valve 182 is closed by the flow in this direction). The expanded gas then flows into the heat exchanger 142 . In heating mode, heat exchanger 142 acts as an evaporator coil and absorbs heat from water circulating in primary water loop 86 . Once the warmed coolant leaves the heat exchanger 142 it is routed back through the diverter valve 170 to the suction side of the compressor 122 .

22 shows an expanded embodiment of the kind shown in FIGS. 19 to 21 . In this version the temperature of the water in the primary water loop 86 is regulated by a heat pump 168 . Three separate micro coolers are connected to the PWL (86). The upper micro cooler exchanges heat through a heat exchanger 192 . The intermediate micro cooler exchanges heat through a heat exchanger (194). The bottom micro cooler exchanges heat through a heat exchanger 196 . Readers should note that the operating mode for each microcooler is independent. The upper microcooler is operating in heating mode. Three of its associated fan control units produce heat and one is shut off. The intermediate micro cooler is also operating in heating mode. Two of the four fan control units are operational. The lower microcooler is operating in cooling mode, three of its four associated fan control units are operating and one is switched off.

22 shows one of the main operational advantages of the present invention. The reader should note in this respect that the upper micro cooler extracts heat from the water circulating through the primary water loop 86 and transfers that heat to the air passing through the associated fan control units. - Although the upper microcooler is at a lower speed because only 2 of its 4 fan control units are operating, while 3 of the 4 fan control units are operating - the middle microcooler also extracts heat from the water in the PWL and there is.

On the other hand, the lower micro cooler is adding heat to the water circulating in the PWL (86). This is true because the lower microcooler is using the heat exchanger 196 as a condenser but flows through its cooling circuit to provide cooling to its fan control units. The reader should be reminded that the water in the PWL 86 is continuously cycled. A consequence of this fact is that the heat added to the PWL through the lower micro cooler is extracted for use by the upper and middle micro coolers. Thus, the present invention transfers thermal energy around the building rather than adding external energy. Some micro coolers will add heat to the PWL but some will extract heat from the PWL. The same can be said for embodiments that incorporate an intermediate water loop between the PWL and one or more micro-coolers. A plurality of micro-coolers connected to one intermediate loop can transfer thermal energy around the intermediate loop (such as transferring heat from a sunny zone on one layer to a dark zone on the same floor).

Of course, the transfer of water loops around or between PWL and intermediate water loops is not 100% efficient. Also, it will not always be possible to maintain the entire building at the desired temperature without adding or subtracting a certain amount of external energy. However, this progressive approach provides a significant increase in efficiency compared to the prior art. The nature of this increase will be described in detail in the "Operating Advantages" section. However, before this description, details of some additional components will be provided.

Component Details - Compressor

The compressor used in the present invention preferably has an unlimited unloading capacity. In HVAC, "unloading" means operating at a capacity less than full capacity. The compressor can preferably vary its speed to match the needs of the space it serves. These compressors do not have to be turned on and off to match the load, but can instead adjust their speed. The smaller the load, the lower the speed. As the speed in the drive motor is reduced, electricity consumption falls in a cubic ratio.

The compressor is also preferably of an oil-free design. As mentioned previously, it may use magnetic bearings, foil bearings, air bearings, or other oil-free technology. In order to circulate the oil in the cooling loop and also to prevent it from collecting far from where it is needed (compressor), conventional oil-based systems have to operate at fairly high loads. In an oil-free system, the compressor can be decelerated to 5% of its rated speed. This characteristic means that the compressor does not need to be completely switched off, but can instead be run at low idle. Compressor life is significantly extended through the use of low idle instead of full shutdown.

In some embodiments, the compressor may be built into the heat exchangers. This arrangement eliminates external cooling pipe work - which always introduces a risk of leakage.

In preferred embodiments, the centrifugal compressor uses an inverter to vary the speed of the compressor. As with all inverters, some form of line reactor is desirable to improve system coordination. These reactors are not 100% efficient and therefore generate heat. In preferred embodiments, the line reactor is embedded in the coolant stream so that the heat generated by the line reactor is rejected back to the condensing circuit. When such a micro cooler is used in heating mode, the heat generated by the line reactor is preferably supplied to the heating circuit, thereby improving its efficiency. In a way to further improve the efficiency, the reactor can be built into the economizer circuit installed between the condenser and the evaporator, one expansion device being replaced by two expansion devices, so that the economizer is halfway between the condensing and evaporating pressures. Operating at the same temperature and pressure, some of the lost energy and latent heat of the condenser liquid is flashed off in the economizer and this gas is then fed back to the compressor. The compressor in this example has first and second stage impellers, and economizer gas is fed to the compressor between the two stages.

Component Details - Heat Exchangers and Expansion Valves

Heat exchangers may vary in style and technology, but in preferred embodiments welded plate heat exchangers are used. The condenser and evaporator used in the cooling loop can preferably be welded as a general heat exchanger assembly. In some versions both the compressor and expansion valve may be integrated within the heat exchanger assembly. Another approach is to have physically separate heat exchangers and also have a compressor mounted as a separate unit or integrated into either the evaporator or condenser. Similarly, the expansion device may be mounted separately, or may be fully integrated into one or both of the heat exchangers.

Component Details - Dehumidification

When the conditioned air requires dehumidification, the cold surface of the coil of the fan control unit (operated in cooling mode) is used to condense and remove moisture from the air. However, although dehumidification is necessary, there are times when the air must be reheated to maintain a comfortable temperature. In this case two coils may be provided in the fan control units. The first coil will circulate cold water from the secondary water loop. A second auxiliary coil will circulate the warm water from the condenser. The cold coil will condense and remove excess moisture and the warm coil will then reheat the air.

Component Details - Fresh Air Supply

Preferred embodiments use an Oil-Pro air blower to supply pressurized fresh air from the central fresh air blower system to the fan control units (FCU). Each FCU preferably has its own throttling device to control the level of fresh air required by each zone at a specific time. Instead of continuously supplying a set amount of fresh air, each FCU will preferably have its own carbon dioxide detector, and since the level of carbon dioxide is monitored, fresh air is introduced into a particular zone only when actually needed. Another option is to pre-dehumidify the air in the fresh air supply circuit, so that the dehumidification load is managed before the air is introduced into the building, which does not require many FCUs, and the FCUs can control situations with a warmer cold water temperature. means

Component Details - System Water Pumps

Each evaporator and condenser is equipped with its own set of cooled water and condenser water pumps, and, as an option, each pump is equipped with a variable speed inverter allowing higher energy efficiency in lower load situations. Each pump is controlled by a micro-chiller system. The water flow is adjusted so that the temperature is maintained correctly throughout its entire cycle.

Component Details - Fan Control Units

Most commercial air conditioners use fan coil units/fan control units (FCU) or air management units (AHU) to cool or heat the air. All of these units do basically the same job, but the FCU usually handles a smaller space and the AHU is usually a duct system and serves a larger space. In this patent, the terms FCU and AHU are, in any case, interchangeable and are intended to describe a device used to heat or cool the air in a given zone and also to control the humidity level. For this reason, the term fan control unit (FCU) is used throughout the detailed description.

Component Details - Primary Water Loop

As explained above, the primary water loop (PWL) in the building is ideally maintained between 20 and 24 °C. Each micro cooler draws heat from or returns heat to the PWL. The temperature of the water circulating in the PWL can be maintained using a variety of conventional HVAC systems. There are two main approaches. First, the water in the PWL can flow through a heat generator (such as a boiler) and then through an evaporative cooler in a cooling tower. Control valves are used to direct water to a heating or cooling device as required. On hot summer days, it may be acceptable for the PWL to rise above 24 °C.

The second major approach is to use a heat pump cooler to regulate the PWL temperature. When the water is outside the range of 20 - 24 °C, the heat pump cooler operates to heat or cool the loop as needed. At many times of the year the PWL is transferring heat around the building and no external thermal energy is required. In other cases, a heat pump or other device is operated to maintain the proper temperature.

In the case of existing buildings, it may be possible to use an existing cooled water or heated water circuit as PWL. As an example, an existing water circuit can be converted so that an existing boiler and an existing cooler can be piped in series or in parallel. Using these advanced micro coolers, conventional coolers can be tuned to provide water at 20 °C rather than the 7 °C required in the prior art. Similarly, the boiler output temperature can be reduced to 22°C instead of the 50°C found in the prior art. This can greatly improve the efficiency of both the boiler and cooler and increase the efficiency of the overall system.

Component Description - Micro Chiller Hardware Units

A physical embodiment of the micro cooler is shown in FIGS. 11 and 12 . The unit is small enough to fit into the existing equipment spaces on each floor and small enough to be moved via an elevator. Therefore, it will not be difficult to retrofit such a unit in an existing building.

Fan control units can be made in various sizes. The smaller version will replace the air resistor in the studio. A larger version can cover the entire zone with the addition of air ducts. The water loop supplying the fan control units does not require large or heavy piping. This can be routed through the double ceilings found in most office buildings.

Component Description - Software-Based Control Units

These inventive embodiments are preferably controlled by a software-based control system. In preferred embodiments, the Predictive Preemptive Automation Control Algorithm (PPACA) is used as part of the overall control system. PPACA is designed to control the energy balance within a specific zone, and the energy balance within the overall system. This means that the PPACA system can control temperature, humidity, capacity, carbon dioxide levels, fresh air, lighting, security, smoke detection and also predict energy consumption from one device. This PPACA is important to the overall output of micro coolers, but also adds flexibility to control conditions, efficiency and overall operation.

The PPACA is integrated into micro cooler systems and is also used to control the micro coolers as well as the control of zones. However, in some cases the PPACA may be supplied as a separate control unit, and in other cases it will be integrated into a central control system or into multiple regional control systems controlling multiple zones. For example, one PPACA may control multiple zones of one floor, or multiple floors, or all zones of an entire building.

For ease of explanation, the control system may use an established communication protocol, such as Bluetooth, to communicate between the various devices being controlled, and may also be remotely controlled by a cell phone or pad. It is also possible to set up the control system to be remotely controlled and inspected by other entities, such as a central control center, or service technicians who may be located anywhere, including off site.

Desirable properties of PPACA are its ability to predict future spot prices of electricity, and the ability to condition each space in advance so that the need to use energy is reduced when energy costs begin to skyrocket. This is done by turning the building into a heat storage battery. PPACA records moment-to-moment electricity spot prices and weather patterns on a daily basis in the PPACA database. This is by accessing the spot price of electricity and projected weather forecasts (preferably using internet-based resources). This allows the system to make its own predictions about when the load in the zone will change, and also allows the system to predict when energy costs will increase and decrease. By making this prediction, it is possible to lower or raise the temperature of each zone in advance when the energy cost is lower, and then reduce the demand on the system when the electric power cost rises. When energy costs are higher, the load is deliberately lowered and the energy stored within the building (cooler air in summer and warmer air in winter) is used to bring the temperature closer to the desired set point. This utilizes the energy stored within the building and effectively turns the building into a heat battery.

operational advantages

A major advantage of the use of the microcooler approach lies in its ability to reduce the pressure ratio inside the cooling circuit of the microcooler itself. The cooling cycle has a “high side” and a “low side”. "High side" refers to the relatively high pressure present from the output side of the compressor to the expansion valve. "Low side" refers to the relatively low pressure present from the downstream side of the expansion valve to the suction side of the compressor. The term “pressure ratio” refers to the ratio between the high side and the low side.

When this advanced micro-chiller is operating in cooling mode, the condenser is maintained between 20 and 24 °C, and the cooled water circulating in the secondary water loop (126 in Fig. 9) is operated between 7 and 24 °C. . This allows the pressure ratio inside the microcooling to vary between 1.05 and 1.4. The pressure ratio varies with the load.

When this advanced micro cooler is operating in heating mode, the condenser operates between 24 and 45 °C and the evaporator operates between 15 and 20 °C. This allows the pressure ratio inside the cooling cycle of the microcooler to vary between 1.1 and 2.9. Similar to the cooling mode, the pressure ratio varies with the load.

The pressure ratio used significantly affects the overall efficiency of the HVAC system. Conventional coolers operate with pressure ratios between 2.2 and 3.8. This higher pressure ratio is less efficient compared to the present invention.

Efficiency in HVAC systems is largely driven by the difference between the desired air temperature and the temperature of the heat "sink" source. The big difference requires a highly loaded HVAC system and consequent reduction in efficiency. Systems based on conventional coolers typically have large temperature differences and thus low efficiencies.

In many cities, the climate is mild most of the year. Although summer and winter do exist, much of the year is spent in mild weather. In mild weather, where temperatures vary throughout the day, and in many cases, buildings require both cooling and heating to operate simultaneously. There may be times when the sun shines on the east wall of the building on a cool morning, and this side of the building needs air conditioning. However, other parts of the building that are not exposed to the sun may still need heating. In this case, the cooler needs to be operated in conjunction with hot water boilers, and in these cases, the plant often pumps both hot water (40-60 °C) and cooled water (7-10 °C) to the entire building. Supply to fan coil units. One of the heating or cooling valves opens in a specific FCU to meet the needs of a specific zone. In each case both the chiller and boiler operate at part load, but each must operate at set-point temperature. Even with small demand, this set point temperature is maintained. In the prior art, two set points must be maintained - approximately 7 degrees and approximately 50 degrees. In this advanced system, one water temperature of approximately 20 degrees is maintained.

Figures 23 and 24 compare the coefficient of performance of this advanced system with respect to two conventional systems. 23 shows a comparison of operation in cooling mode. The load range shows operations between 20% and 100% of maximum capacity. The vertical line shows the Integrated Part Load Value (IPLV) average load. Upper curve 198 shows the coefficient of performance (COP) at various loads of this advanced micro cooler system. Middle curve 200 shows the COP of a chiller system using a compressor with magnetic bearing technology, such as sold by Danfoss Turbocor of Tallahassee, Florida. Lower curve 202 shows the COP of a conventional chiller system using an air-cooled chiller. As the reader observes that this advanced system has a higher COP at all load levels, the efficiency gains become more dramatic at lower load levels. 24 shows the same comparison of combined heating and cooling cycles. The reader will therefore appreciate that the present invention provides significant efficiency advantages over the prior art.

25 shows a plot of the pressure ratios of this advanced micro-chiller system compared to conventional systems. For a typical range of loads, this advanced system uses a lower pressure ratio and thereby achieves higher efficiency. The plots shown are in fact conservative and the advantages of this progressive system are generally greater than those shown.

The invention includes many additional features and embodiments, which may be combined in numerous ways. Additional exemplary features and implementations include:

1. Although water has been described as the preferred circulating medium, many other materials may be used in place.

2. The embodiment of Figures 8-10 can be modified such that the coolant circulation is reversed but the water circulation in the secondary water loop is still constant. In this embodiment, the roles of the two heat exchangers will be reversed through a change in the direction of circulation of the coolant. A diverter valve (as shown in FIG. 20 ) may be used for this purpose.

3. In embodiments using foil bearings in the compressor, it is desirable not to allow the compressor speed to drop below the "liftoff" speed of the foil bearing. In these cases, the control system can set the compressor to operate slowly while the water flow control valves periodically reverse so that the heating and cooling modes are cycled and no net heating or cooling is applied to the air passing through the fan control units. there is.

4. Since the temperature of the water in the PWL will be close to the temperature of the air inside the building, the insulation requirements of the PWL will be much smaller than that of conventional hot and cold water loops.

5. The Predictive Preemptive Automation Control Algorithm (PPACA) predicts future HVAC loads (short-term) and also predicts energy prices. To reduce operating costs, PPACA has the ability to use the building as a “thermal battery”. For example, PPACA can reduce the temperature of a building to sub-optimal during periods of low energy, reducing this "stored cooling" while operating at a lower capacity during periods of high energy.

6. PPACA can be set up to give different priorities to different HVAC zones of a building. Some zones can be set up to maintain a desired temperature regardless of energy cost, while others are allowed to vary widely for insulation. As an example, operating rooms in a hospital may be considered "critical" to ensure that a set temperature is maintained under any circumstances. Administrative offices within the same hospital building may be allowed to warm up during periods of rising costs.

7. In a conventional system, hot and cold water are maintained at a constant temperature, and water bypass valves are used to set the flow of water through various air regulators. The amount of water flowing through a particular air regulator is set by a diversion or flow through a three way valve. These valves allow enough water to flow through the coil of a particular air conditioner to provide the required amount of cooling or heating. The remainder of the water bypasses the coil and connects back to the return line on the other side of the coil. This creates wasteful recycling. In the present invention, the flow rate is fairly constant through the coil, and the capacity is adjusted by changing the temperature of the water (rather than the water flow rate). This fact allows the present invention to operate with much higher efficiencies than conventional methods. This fact also allows the use of a lower pressure ratio in the micro-chiller cooling circuit, which reduces the required compressor speed. Electrical energy consumption is reduced by the cube ratio when the compressor speed is halved. Conventional chiller loading and unloading is controlled by maintaining the feed or return water at a constant temperature. Because conventional systems can handle the unpredictable full load conditions of the air conditioner, most machines use the same feed temperature as the control point. In the present invention, loading and unloading are controlled on a zone basis. The capacity of each microcooler is controlled by the actual ambient temperature of the zone it controls. The closer the room's temperature is to the set point, the slower the compressor will run, and the more efficient it will be.

Although the foregoing detailed description contains important details, it is provided for the purpose of description of preferred embodiments of the invention and should not be construed as limiting the scope of the invention. Accordingly, the scope of the invention should be fixed by the claims ultimately expressed rather than by the examples given.

10 building
12th floor
14 chiller plant
16 hot water plant
18 air handler
20 air duct system
24 cooling tower
26 circulation pump
27 circulation pump
28 cold water loop
30 circulation pump
32 cooling tower circuit
34 input power
36 gas inlet
38 exhaust flue
40 hot water loop
42 recirculation fan
44 main fan
46 intake
48 exhaust
50 air valve
52 air valve
54 air valve
56 throttling valve
58 throttling valve
60 center zone
62 east zone
64 north zone
66 west zone
68 south zone
70th floor
72 delivery register
74 distribution duct
76 center zone air handler
78 East zone air handler
80 north zone air handler
82 West zone air handler
84 south zone air handler
86 primary water loop
88 primary water loop regulation system
90 micro chiller
92 fan control unit
94 return line
96 feed line
98 valve
100 valve
102 valve
104 valve
106 valve
108 valve
110 valve
112 valve
114 pump
116 pump
118 heat exchanger
120 heat exchanger
122 Compressor
124 expansion valve
126 secondary water loop
128 chassis
130 reversing valve assembly
132 connection point
134 controller housing
136 fresh air duct
138 air control valve
140 recirculation air inlet
142 heat exchanger
144 intermediate water loop
146 first micro chiller
148 Second micro chiller
150 third micro chiller
152 first secondary water loop
154 second secondary water loop
156 third secondary water loop
158 evaporative condenser
160 boiler
162 pump
168 heat pump
170 reversing valve
172 valve
174 valve
176 valve
178 valve
180 expansion valve
182 check valve
184 check valve
186 coil
188 refrigerant circulation loop
190 Alternate micro chiller
192 heat exchanger
194 heat exchanger
196 heat exchanger
198 micro chiller curve
200 magnetic bearing curve
202 Conventional cooling curve

Claims (20)

A method of controlling the temperature of a space in a building, the method comprising:
(a) providing a fan control unit having a liquid coil and a fan, the fan configured to blow air over the liquid coil and into the space;
(b) providing a micro cooler comprising:
(i) a compressor;
(ii) a condenser;
(iii) an expansion valve;
(iv) an evaporator, and
(v) a coolant circulation loop configured to circulate coolant from the compressor to the condenser, to the expansion valve, to the evaporator, and back to the compressor;
(c) providing a primary liquid loop flowing through the building;
(d) providing a secondary liquid loop flowing between the micro cooler and the fan control unit;
(e) maintaining said primary liquid loop between 18 °C and 26 °C;
(f) providing a first set of valves controlling the flow of the micro-cooler through the evaporator;
(g) providing a second set of valves controlling the flow of the micro-cooler through the condenser;
(h) setting said first set of valves to circulate liquid in said primary liquid loop through said evaporator and circulate liquid in said secondary liquid loop through said condenser when said space requires heating; establishing a second set of valves;
(i) setting said first set of valves to circulate liquid in said secondary liquid loop through said evaporator when heating is required in said space and to circulate liquid in said primary liquid loop through said condenser; establishing a second set of valves;
How to control the temperature of a space within a building. 2. The method of claim 1 comprising maintaining the primary liquid loop between 20 °C and 24 °C.
How to control the temperature of a space within a building. The method of claim 1 , wherein the primary liquid loop and the secondary liquid loop contain water.
How to control the temperature of a space within a building. 2. The method of claim 1, wherein the first set of valves comprises a spool valve.
How to control the temperature of a space within a building. 5. The method of claim 4, wherein the second set of valves is contained within the spool valve.
How to control the temperature of a space within a building. 2. The method of claim 1, further comprising the step of providing a second fan control unit attached to the secondary liquid loop.
How to control the temperature of a space within a building. 2. The method of claim 1, further comprising unloading the compressor and periodically cycling the first set of valves and the second set of valves between a heating mode and a cooling mode.
How to control the temperature of a space within a building. A method of controlling the temperature of a space in a building, the method comprising:
(a) providing a fan control unit having a liquid coil and a fan, the fan configured to blow air over the liquid coil and into the space;
(b) providing a micro cooler comprising:
(i) a compressor;
(ii) a condenser;
(iii) an expansion valve;
(iv) an evaporator, and
(v) a coolant circulation loop configured to circulate coolant from the compressor to the condenser, to the expansion valve, to the evaporator, and back to the compressor;
(c) providing a primary liquid loop flowing through the building;
(d) providing a secondary liquid loop flowing between the micro cooler and the fan control unit;
(e) maintaining said primary liquid loop between 18 °C and 26 °C;
(f) circulating liquid in the primary liquid loop through the evaporator and in the secondary liquid loop through the condenser when the space requires heating;
(g) circulating liquid in the secondary liquid loop through the evaporator and in the primary liquid loop through the condenser when the space requires heating;
How to control the temperature of a space within a building. 9. The method of claim 8 comprising maintaining the primary liquid loop between 20 °C and 24 °C.
How to control the temperature of a space within a building. 9. The method of claim 8, wherein the primary liquid loop and the secondary liquid loop contain water.
How to control the temperature of a space within a building. 9. The method of claim 8, wherein flow through the evaporator is controlled by a spool valve.
How to control the temperature of a space within a building. 12. The method of claim 11, wherein flow through the condenser is controlled by the spool valve.
How to control the temperature of a space within a building. 9. The method of claim 8, further comprising providing a second fan control unit attached to the secondary liquid loop.
How to control the temperature of a space within a building. 9. The method of claim 8, further comprising unloading the compressor and periodically cycling the microcooler between a heating mode and a cooling mode.
How to control the temperature of a space within a building. In the method of independently controlling the temperature of the first space in the building and the second space in the building,
(a) providing a first fan control unit having a first liquid coil and a first fan, wherein the first fan is configured to blow air over the first liquid coil and into the first space;
(b) providing a first micro cooler comprising:
(i) a first compressor;
(ii) a first condenser;
(iii) a first expansion valve;
(iv) a first evaporator, and
(v) a first coolant circulation loop configured to circulate coolant from the first compressor to the first condenser, to the first expansion valve, to the first evaporator, and back to the first compressor;
(c) providing a primary liquid loop flowing through the building;
(d) providing a first secondary liquid loop flowing between the first micro cooler and the first fan control unit;
(e) providing a second fan control unit having a second liquid coil and a second fan, wherein the second fan is configured to blow air over the second liquid coil and into the second space;
(f) providing a second micro-cooler comprising:
(i) a second compressor;
(ii) a second condenser;
(iii) a second expansion valve;
(iv) a second evaporator, and
(v) a second coolant circulation loop configured to circulate coolant from the second compressor to the second condenser, to the second expansion valve, to the second evaporator, and back to the second compressor;
(g) providing a second secondary liquid loop flowing between the second micro cooler and the second fan control unit;
(h) maintaining said primary liquid loop between 18 °C and 26 °C;
(i) circulating liquid in the primary liquid loop through the first evaporator and in the first secondary liquid loop through the first condenser when heating is required in the first space;
(j) circulating liquid in the first secondary liquid loop through the first evaporator and in the primary liquid loop through the first condenser when heating is required in the first space;
(k) circulating liquid in the primary liquid loop through the second evaporator and in the second secondary liquid loop through the second condenser when heating is required in the second space;
(l) circulating liquid in the second secondary liquid loop through the second evaporator and circulating the liquid in the primary liquid loop through the second condenser when heating is required in the second space; doing,
A method of independently controlling the temperature of a first space within a building and a second space within the building. 16. The method of claim 15 comprising maintaining the primary liquid loop between 20 °C and 24 °C.
A method of independently controlling the temperature of a first space within a building and a second space within the building. 16. The method of claim 15, wherein the primary liquid loop and the secondary liquid loop contain water.
A method of independently controlling the temperature of a first space within a building and a second space within the building. 16. The method of claim 15, wherein flow through the evaporator is controlled by a spool valve.
A method of independently controlling the temperature of a first space within a building and a second space within the building. 19. The method of claim 18, wherein flow through the condenser is controlled by the spool valve.
A method of independently controlling the temperature of a first space within a building and a second space within the building. 16. The method of claim 15, further comprising providing a second fan control unit attached to the secondary liquid loop.
A method of independently controlling the temperature of a first space within a building and a second space within the building.

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